Fix compile warning:

spetrunia · spetrunia · commit b30446c85dbf · 2020-03-11T13:46:57.000+03:00
It was:
implicit conversion from 'ha_rows' (aka 'unsigned long long') to 'double'
changes value from 18446744073709551615 to 18446744073709551616

Follow what JOIN::get_examined_rows() does for similar code.
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
@@ -4267,7 +4267,7 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
       for (i= 0; i < join->table_count ; i++)
         if (double rr= join->best_positions[i].records_read)
           records= COST_MULT(records, rr);
-      ha_rows rows= records > HA_ROWS_MAX ? HA_ROWS_MAX : (ha_rows) records;
+      ha_rows rows= records > (double) HA_ROWS_MAX ? HA_ROWS_MAX : (ha_rows) records;
       set_if_smaller(rows, unit->select_limit_cnt);
       join->select_lex->increase_derived_records(rows);
     }

Original file line number	Diff line number	Diff line change
`@@ -4267,7 +4267,7 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,`
`4267`	`4267`	`for (i= 0; i < join->table_count ; i++)`
`4268`	`4268`	`if (double rr= join->best_positions[i].records_read)`
`4269`	`4269`	`records= COST_MULT(records, rr);`
`4270`		`- ha_rows rows= records > HA_ROWS_MAX ? HA_ROWS_MAX : (ha_rows) records;`
	`4270`	`+ ha_rows rows= records > (double) HA_ROWS_MAX ? HA_ROWS_MAX : (ha_rows) records;`
`4271`	`4271`	`set_if_smaller(rows, unit->select_limit_cnt);`
`4272`	`4272`	`join->select_lex->increase_derived_records(rows);`
`4273`	`4273`	`}`